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Project-declaredLean 4.31.0 · mathlib@fabf563a

Lex'Order prop

Lex'Order.Lex'Order_prop

Project documentation

Existence theorem packaging the lexicographic construction. It produces a LinearOrder (Finset α) with two convenient properties: 1. Subset-monotonicity: A ⊆ B implies A ≤ B. 2. Singleton compatibility: comparing singleton finsets recovers the original order on α. API note: returning the order via ∃ lo allows users to avoid a global instance and...

Exact Lean statement

theorem Lex'Order_prop (α : Type*) [lo : LinearOrder α] : ∃ lo : LinearOrder (Finset α),
(∀ A B : Finset α, A ⊆ B → lo.le A B) ∧
(∀ a b : α, a ≤ b ↔ lo.le {a} {b})

Formal artifact

Lean source

Canonical source
Full Lean sourceLean 4
theorem Lex'Order_prop (α : Type*) [lo : LinearOrder α] :  lo : LinearOrder (Finset α),( A B : Finset α, A  B  lo.le A B) ( a b : α, a  b  lo.le {a} {b}) := by  use Lex'LinearOrder  constructor  · intro A B h    unfold LE.le Preorder.toLE PartialOrder.toPreorder      LinearOrder.toPartialOrder Lex'LinearOrder LexLE    if heq : A = B then      right      constructor      · exact congrArg Finset.card heq      · rw [heq]    else      left      apply Finset.card_lt_card      exact Finset.ssubset_iff_subset_ne.2 h,heq  · intro a b    unfold LE.le Preorder.toLE PartialOrder.toPreorder      LinearOrder.toPartialOrder Lex'LinearOrder LexLE    simp only [SemilatticeInf.toPartialOrder, Lattice.toSemilatticeInf,      SemilatticeSup.toPartialOrder, Lattice.toSemilatticeSup, DistribLattice.toLattice,      instDistribLatticeOfLinearOrder, LinearOrder.toLattice, LinearOrder.toPartialOrder,      Finset.card_singleton, lt_self_iff_false, Finset.sort_singleton, true_and, false_or]    constructor    · intro h      unfold LE.le List.LE' Preorder.toLE PartialOrder.toPreorder        LinearOrder.toPartialOrder List.instLinearOrder      simp only [List.lex_lt, List.cons.injEq, and_true]      if h' : a = b then        exact Or.inl h'      else        right        unfold LT.lt List.instLT        simp only [List.lex_singleton_iff]        exact lt_of_le_of_ne h h'    · intro h      unfold LE.le List.LE' Preorder.toLE PartialOrder.toPreorder        LinearOrder.toPartialOrder List.instLinearOrder at h      simp only [List.lex_lt, List.cons.injEq, and_true] at h      rcases h with h | h      · exact le_of_eq h      · unfold LT.lt List.instLT at h        simp only [List.lex_singleton_iff] at h        exact le_of_lt h
Project
Harder-Narasimhan
License
Apache-2.0
Commit
20220e90b72c
Source
HarderNarasimhan/OrderTheory/Lex'Order.lean:172-216

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Project-declaredLean 4.31.0

Associated Primes ker mk Linear Map eq

HarderNarasimhan.CommutativeAlgebra.associatedPrimes_ker_mkLinearMap_eq

Project documentation

Associated primes of the kernel of the localization map. This identifies the associated primes of ker (LocalizedModule.mkLinearMap S M) : Submodule R M with the associated primes of M that do meet the multiplicative set S. Equivalently, these are the associated primes of M after removing those disjoint from S. This lemma is used as the “kernel...

algebraic geometryvector bundlescategory theory

Source project: Harder-Narasimhan

Person-level attribution pending.

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Project-declaredLean 4.31.0

Associated Primes ker mk Linear Map subset

HarderNarasimhan.CommutativeAlgebra.associatedPrimes_ker_mkLinearMap_subset

Plain-language statement

One-sided inclusion for associated primes of the kernel of the localization map. If p ∈ associatedPrimes R (ker (mkLinearMap S M)), then p is an associated prime of M and p is not disjoint from the multiplicative set S. This is one direction of associatedPrimes_ker_mkLinearMap_eq.

algebraic geometryvector bundlescategory theory

Source project: Harder-Narasimhan

Person-level attribution pending.

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Project-declaredLean 4.31.0

Associated Primes localized Module subset disjoint

HarderNarasimhan.CommutativeAlgebra.associatedPrimes_localizedModule_subset_disjoint

Plain-language statement

Associated primes of a localized module are disjoint from the multiplicative set. More precisely, if p ∈ associatedPrimes R (LocalizedModule S M), then p.carrier ∩ S = ∅. This is a standard fact in commutative algebra: an element of S becomes a unit after localization, so no associated prime of the localized module can contain an element of S.

algebraic geometryvector bundlescategory theory

Source project: Harder-Narasimhan

Person-level attribution pending.

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